The consumption of high levels of triglyceride lipids has been associated with a number of health problems. Currently, obesity is one of the more prevalent metabolic problems among the general population. This condition in many people is attributed to the ingestion of a greater number of calories than is actually needed to supply energy for the maintenance and functioning of the body. Lipids are the most concentrated form of energy in the diet, with each gram of a triglyceride contributing about nine calories.
Maintaining a strict low fat diet, however, is difficult due to the fact that most persons prefer the taste of "rich" foods, that is, foods that have the satisfying mouthfeel associated with fats and oils. In order for a reduced calorie food composition to satisfactorily replace a conventional foodstuff, the fat substitute used in its preparation must mimic as closely as possible the organoleptic qualities of a triglyceride. The fat substitute must additionally have physical properties (viscosity, melting point, heat stability, thermal conductivity, etc.) resembling those of natural lipids since such properties often play a key role during preparation of a food composition. For example, in deep fat frying the oil acts as a heat transfer medium so as to impart crispiness to the food being fried. At the same time, the ideal fat substitute should be non-toxic and should not cause any undesirable gastrointestinal side effects such as anal oil leakage, gas formation or diarrhea. This combination of attributes has in practice been quite difficult to achieve; the need to develop completely acceptable reduced calorie fat substitutes thus still exists.
U.S. Pat. No. 5,219,604 (Klemann et al.) teaches the use in fat substitutes of inter- and intramolecular ester bridges of the formula --O--(CO)--(CH.sub.2).sub.n --(CO)--O-- where n is 1 to 8 formed by reacting dibasic acids with hydroxyl groups on the fatty side chains of fat compounds. Such fat substitutes, through the incorporation of hydroxy acids, thus inherently contain multiple ester linkages capable of being hydrolyzed upon ingestion. Where such hydrolysis takes place, the resulting hydrozylates are susceptible to further digestion; such fat substitutes may therefore have a higher level of available calories than otherwise would be desirable. Moreover, hydroxy fatty acids have certain deleterious physiological effects. The use of hydroxy fatty acids to prepare a fat substitute thus may not be desirable if digestion of the fat substitute will release such substances in the digestive tract.